1. Field of the Invention
The present invention relates to a method and an apparatus for producing a decorative sheet that is laminated of a first resin sheet, having a pictured layer, and a second resin sheet having embossed patterns. The fabricated decorative sheet is used in production of a decorative board by being joined onto the surface of a wooden board, an inorganic board, metallic board or the like.
2. Description of the Related Art
As an outer surface material of a decorative board, a decorative sheet that, for example, is laminated of a first resin sheet having a woodgrain pictured layer and a second resin sheet having woodgrain emboss patterns is used. The decorative board having the decorative sheet provides a woody feeling caused by the woodgrain emboss patterns in addition to the woodgrain picture.
Conventionally, the decorative sheet is produced by the following steps: an emboss roller embosses patterns onto a sheet which is moltenly extruded from a molten-resin extrusion means, and then a sheet having the pictured layer is laminated on the underside of the embossed sheet.
As materials of the decorative sheet, instead of generally used polyvinyl chloride, the use of a polyolefin type resin (see Japanese Patent Laid-open No. Hei8-34058 and Japanese patent Laid-open No. Hei8-132577) or a resin containing polypropylene and a polyolefin type flexible component (see Japanese Patent Laid-open No. Hei8-1881) has been proposed from the viewpoint of safeguarding the environment from hydrogen chloride gas that is produced in an incinerating process.
The aforementioned resin avoids the environmental disruption, but, on the other hand, the sheet could expand and contract when the first and second resin sheets are mutually laminated according to the conventional method for producing the decorative sheet. Especially, if ink is coated on the embossed patterns of the resin sheet, the inconsistency between the positions of the embossed pattern and the picture on the sheet is more noticeable when the expanded or contracted sheets are mutually laminated, therefore the original design cannot be obtained on the decorative sheet.